1. Field of the Invention
This invention relates to an automatic accompaniment instrument which is adapted to automatically generate accompaniment tones such as chord background tones, bass tones, and percussion instrument tones according to a predetermined pattern, based on a chord progression, a kind of rhythm, etc. which have been designated.
2. Prior Art
An automatic accompaniment instrument has already been proposed, e.g. by Japanese Provisional Patent Publication (Kokai) No. 63-193199, which reads accompaniment data from accompaniment pattern data stored in C major key, and then subject the read accompaniment data to pitch conversion according to a chord input thereto, to thereby reproduce an accompaniment tone. According to this proposed instrument, the pitch conversion of accompaniment data is performed by controlling the pitch of an accompaniment none according to the type of the input chord and a difference in pitch between the root of the input chord and the read accompaniment data, and then shifting the pitch of the accompaniment data according to the root of the input chord.
However, according to the proposed instrument, the pitches of accompaniment tones are sequentially controlled by chords input thereto. As a result, if the chord is changed, this can result in a large difference in pitch between a tone generated based on a chord immediately preceding the change and a tone generated based on a chord immediately following the change, causing an unnaturalness in the flow of accompaniment tones reproduced.